Reference Data

Changes in chromatin structure play a large role in the regulation of transcription in eukaryotes (1). The nucleosome is the primary building block of chromatin, and is made up of four core histone proteins (H2A, H2B, H3 and H4) (2). Acetylation of core histones regulates gene expression (2). Histone H3 is primarily acetylated at lysines 9, 14, 18, and 23 (3,4). Acetylation at lysine 9 appears to have a dominant role in histone deposition and chromatin assembly in some organisms (3,4). Phosphorylation at Threonine 11 occurs preferentially at the centromere from prophase to anaphase (5).